(CNN) -- A European Union police officer was killed in a shooting in northern Kosovo on Thursday morning, the first police officer on the EULEX mission to be killed there, a mission spokeswoman said.
The officer died when gunmen fired on two EULEX mission vehicles carrying six staffers in Mitrovica, spokeswoman Irina Gudeljevic told CNN.
She said that a murder investigation had been launched.
Kosovo declared independence from Serbia in February 2008 after years of ethnic tensions.
Serbia does not recognize the declaration, and the European Union is trying to work out a dialogue between the two sides.
Tensions between ethnic Serbs and ethnic Albanians have escalated in recent years, especially in northern Kosovo, according to the United Nations.
The world body has expressed concerns about the region, which it says has an ethnic Serbian majority. Ethnic Albanians are the majority in the rest of Kosovo.
CNN's Faith Karimi contributed to this report